The present disclosure relates to a document feeding device that conveys a document to a document reader, and an image forming apparatus provided with the document feeding device.
A document feeding device generally causes a document to be nipped at nips formed between a plurality of drive rollers disposed at predetermined intervals in a direction orthogonal to a feeding direction and a plurality of driven rollers disposed to face the drive rollers, respectively, feeding the document to a document reader through the rotation driven by the drive rollers. If the nips formed between a plurality of facing pairs of rollers are aligned in a direction orthogonal to the feeding direction, a rear end of the fed document will be released from the nips simultaneously or substantially simultaneously, when the document is fed by such a document feeding device. Since a feeding load drastically changes (reduces) at the moment of the rear end of the document being released from the nips, a feeding speed of the document temporarily accelerates. This may affect the feeding speed of the document in the document reader, leading to defective reading.
In order to reduce such change in the feeding load, a document feeding device has been conventionally proposed in which nips are formed not in line with each other in a direction orthogonal to a feeding direction. This is implemented by arranging respective rotational shafts of a plurality of rollers, either a plurality of drive rollers or a plurality of driven rollers, offset with respect to the feeding direction.